The motor is a 5.3 out of a truck with an aftermarket generic comp cam grind that he got for a good deal. The cam is a bit large IMO for the cubes and lower compression of the 5.3l bottom end but will work well on bottle. The heads are stock 5.3l heads with some quickie light clean up and milling but still uses the stock valves. Stock 5.3l heads are the worst flowing LS head out there especially with stock valves in them, the light porting that was done probably didn't do anything so I would just consider it a small clean up job on old heads. It could easily pick up another 40 rwhp just from doing some real ported 5.3l castings with bigger valves, etc. Could probably use a ported stocker TB too for another 5-10 rwhp.